In known bodymakers, cups are fed to the bodymaker and carried by a punch on the end of the ram, through a series of ironing dies to obtain the desired size and thickness of the can. Ultimately, the can body carried on the punch may contact a bottom forming tool so as to form a shape such as a dome on the base of the can. The ram is driven through a link at one end of a pivoted lever. The lever is connected to a driven crankshaft by a connecting rod and converts arcuate motion of the crankshaft into linear motion of the ram. Where the ram motion is horizontal, bearings in a cradle or frame are required to support the ram.
The height of the resultant can body is dictated predominantly by the stroke of the bodymaker. In order to make different can sizes, it is generally considered impractical to use a single machine and therefore it is customary to use different bodymakers and associated tooling for each different can size. The only possible known way of using a single machine for different can sizes would require use of a standard long stroke machine which operates at slow speed for tall cans. For shorter can sizes it is then necessary to rearrange the tooling and operate the same machine at the same stroke length and speed, which is slower than is usual for making shorter can sizes. Alternatively, the tall cans are simply cut down to the desired smaller can size. Clearly neither of these approaches is economically viable.
If a diameter and height change is needed, a ram having a smaller diameter than is conventional has been tried with the punch at the end of the ram changed for different can height and/or diameter. However the use of a smaller diameter ram for a long stroke machine means that the ram is likely to droop excessively on the return stroke. The large punch would therefore risk damaging tooling as it moves through the machine.